This invention relates generally to the field of waste stripping and more particularly is directed to an apparatus and a method for automatically stripping waste material from previously die cut blanks.
In the cardboard box and corrugated carton industry, it is the usual practice to form sheet materials such as cardboard and corrugated board into rectangular blanks and then to design a package configuration in the blank. By utilizing conventional die cutting apparatus, the usable portions of the blank are defined from the waste portions. The positive separation of the waste material to be trimmed from the usable portions of the blank has continuously presented both practical and economic problems in the industry.
One of the older and still used techniques that is commonly employed throughout the industry is the practice of stacking a plurality of previously die cut sheets into piles wherein all of the blanks are placed in registry one above the other. Then, by utilizing conventional hand tools, the waste materials can be manually removed or stripped from the plurality of the stacked sheets or blanks at the same time. It is usual to accomplish this waste trimming function in a relatively slow operation by engaging one or more employees to physically separate the waste from the remainder of the blank. The workers usually employ hammers or other types of impact applying tools and one or more employees per shift are required for this duty. The end result of these old practices is to accomplish the desired waste stripping operations, but in a slow and costly procedure.
In more modern approaches to the same problem, other prior workers have sought to utilize automatic machinery to mechanically strip the waste from the remainder of the blank. Such prior art machines have employed vibrating mechanisms, punching mechanisms and in one of the applicant's own earlier designs, a rotary stripping wheel. The stripping wheel type of waste removal apparatus is fully disclosed in the applicant's prior U.S. Pat. No. 3,889,863.
While the prior art methods of waste removal are generally effective in removing or trimming the waste from the usable portion of the blank, such prior art methods and machines have not found one hundred percent acceptance in the industry. This lack of acceptance could be due to the economic disadvantages inherent in the system, the fact that in certain of the mechanical designs peak efficiency could not be achieved or because such prior art machines could only be adjusted after elaborate set-up procedures. Such complicated set-up required skilled personnel and extended periods of down time every time the blank size was changed, thereby detracting from the other advantages that may have been present in the operating concept of the machine.